headcode

noun

1. (UK)A code used to distinguish classes of train for the benefit of signalmen, formerly by using white oil lamps (or white discs) placed on brackets on the front of the locomotive. The various lamp positions defined the class of train.

   “Another appendix elucidates the S.E.C.R. headcode system.”

   “Gaining a new headcode, it is then rebranded as the 2103 Carmarthen-Fishguard Harbour - a place I'd never visited by rail.”